Field of the Invention
The present invention relates to an injection molding machine with an ejector and an ejector operating method for the injection molding machine.
Description of the Related Art
In general, mold opening/closing operation and ejector advancing/retracting operation, which are mold operations of an injection molding machine, are performed based on previously input settings when predetermined operation start conditions are satisfied by sequence control during continuous molding operation.
A mold has a through-hole defined between a mold mounting surface and an ejector plate. An ejector device, such as an ejector rod, of the injection molding machine can be directly advanced through the through-hole. Further, a return spring is attached to the ejector plate.
In position condition setting for ejector operation of the injection molding machine, it is common to set a position in which the ejector plate is completely retracted by the return spring so that the ejector plate and the ejector device of the injection molding machine are just disengaged from each other.
Japanese Patent Application Laid-Open No. 2000-326371 discloses a technique in which an ejector device of an injection molding machine is operated at a higher speed before ejector pins abut against a mold than while an ejector plate is urging the mold to advance.
In the technique disclosed in Japanese Patent Application Laid-Open No. 2000-326371, the ejector device is certainly operated at a high speed before the ejector pins abut against the mold. Since the speed at which the ejector plate urges the mold to advance is a conventional speed, however, the overall rate of time reduction may be low in some cases.
If the set command speed for an ejector is simply increased in order to reduce the ejector operating time, moreover, the set speed sometimes cannot be reached when the advance distance of the ejector is short.